Stereotactic Biopsy of Intracranial Processes

Abstract

For CT-stereotaxis many methods are in use. Here we present our CT-stereotaxis method. The stereotactic device developed by Riechert and Mundinger in the Computer compatible version of Mundinger and Birg is fixed at the CT-table by means of a special adjustable holder (Figs. 1 and 2). If the center point of our stereotactic device coincides with the image haircross of the Scanner and the headring is plane parallel to the CT-scanning plane (Fig. 3), all the coordinates measured at the CT-screen also hold true for the stereotactic device: no calculation for any stereotactic coordinate, no further reference frame are necessary!

The accuracy of the method was tested with our stereotactic phantom: the measurements showed a maximum deviation of 0.6 mm from the predetermined position. For functional and non-functional interventions, our method is very easy to use. In the case of stereotactic biopsy, implantation of radionuclides, of catheter or DBS-systems we take CT-slices of 1.5–5 mm. Then, with the CT-program, the structure in question (tumor, cyst) (Fig. 4) is traced and the target points are measured and marked. At the sagittal and coronal reconstructions the trepanation point is determined (Figs. 5, 6). For control purposes all coordinates measured on the CT are transferred to the X-rays (Figs. 7 and 8). Then the Computer gives us the setting parameters for our stereotactic device and the operation begins.